Hypoxis hemerocallidea (African Potato): A Botanical Whose Time Has Come?

Chapter 4

Hypoxis hemerocallidea (African potato):A Botanical Whose Time Has Come?

David R. Katerere*

Department of Pharmaceutical Science, Faculty of Science, TshwaneUniversity of Technology, Arcadia campus, Pretoria, 0001, South Africa

*E-mail: [email protected].

Hypoxis hemerocallidea is one of Southern Africa’s mostimportant and popular medicinal plants. It is used for a widea range of traditional medical treatments including urinarytract infections, heart disease, infertility and anxiety. It’smost popular contemporary use is for prostate disorders forwhich there is increasingly good evidence about it’s efficacy.Phytosterols are thought to be the main bioactive compoundsfor this indication and also for anti-lipidemic, anti-diabetic andanti-inflammatory properties exhibited by hypoxis extracts.

Despite the popularity of hypoxis as a herbal and botanicalmedicine, the research into it’s pharmacological application hasnot been of sufficient depth and width to prove it’s utility inmodern medicine. Recent data using a colitis model presentsan exciting new avenue which might finally yield products.However there continues to be a need for sustained in vitro andmore importantly in vivo studies if this useful plant is be fullyexplored.

Introduction

Traditional medicine has experienced a resurgence in Africa in recent times.This is largely to do with a new sense of cultural pride following independencefrom colonial authorities who sought to suppress such practices during theirtenure (1). In post-colonial Africa, there has also been limited access to allopathicmedical services. Further, the emergence of new diseases such as HIV, and

© 2013 American Chemical Society

Dow

nloa

ded

by T

SHW

AN

E U

NIV

OF

TE

CH

NO

LO

GY

on

Oct

ober

30,

201

3 | h

ttp://

pubs

.acs

.org

P

ublic

atio

n D

ate

(Web

): O

ctob

er 4

, 201

3 | d

oi: 1

0.10

21/b

k-20

13-1

127.

ch00

4

In African Natural Plant Products Volume II: Discoveries and Challenges in Chemistry, Health, and Nutrition; Juliani, H., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2013.

previously unknown chronic diseases e.g. diabetes and cancer, most of whichhave no known medical cures has accelerated the growth of Complementary andAlternative Medicine (CAM) (2, 3)

WHO estimates that 80% of the world’s population still largely relies ontraditional medicine to meet it’s healthcare needs (4). South Africa has 7000plants which are used in traditional medicine (5–7). One of the most famous, andcertainly the most controversial is Hypoxis hemerocallidea. Commonly known asAfrican potato, this herb was until recently widely promoted by a now deceasedSouth African minister of health as an alternative to treatment of HIV / AIDS (8,9) this despite little or no supporting scientific evidence (10).

Botanical Information

Hypoxis hemerocallidea Fisch. & C.A. Mey, previously known as H. rooperibelongs to the family Hypoxidaceae which consists of 8 genera (11). Based onsimilarities with species of the Amaryllidaceae and Liliaceae family, the generawere previously classified in these taxa (12).

The hypoxis genus contains 130 species including H. hemerocallidea, H.acuminate, H. iridifolia and H. rigidula of which the first is most widely usedand is therefore the primary focus of this chapter. The moniker African potato isto some extent a misnomer as the rootstock is a corm rather than a tuber and thename causes confusion with tuberous Plectranthus esculentus (13). There is someevidence that the common hypoxis species are used interchangeably in traditionalmedical practice, sometimes inadvertently because of their close similarities (14).

Hypoxis grows as a stemless, perennial geophyte with large black fibrouscorms which are bright yellow inside when freshly cut (15). The leaves areorganized typically into three ranks and maybe slightly hairy. The flowerswhich appear between October and January (16) are star-shaped and brightyellow and the number per inflorescence may vary from two to twelve (15,17). While it is indigenous to southern Africa, hypoxis has a world-widecosmopolitan distribution. It grows widely in the savanna grasslands of SouthAfrica, Swaziland, Lesotho , Mozambique, Zimbabwe and into some parts ofEast Africa (11, 16). It has also been reported to grow in meanders, grasslandsand mountains of South America, Australia and coastal areas of Asia (18).

Traditional and Contemporary Use

The rootstock of Hypoxis is the plant part of choice for medicinal and dietaryuse. It is the iconic African potato promoted by proponents of African traditionalmedicine in South Africa as a cure-all and derided by opponents as quackery (19)in the country’s highly charged political environment at the turn of the century.In Zulu traditional medicine it is widely known as “zifozonke” literally meaning“panacea” (20). It is known as African potato, starflower / South African stargrass, Ilabatheka, Inkofe (in Zulu), sterretjie (in Afrikaans), moli kharatsa, monnawa maledu, thitidi (in Sotho), hodzori (in Shona) (21).

52

Dow

nloa

ded

by T

SHW

AN

E U

NIV

OF

TE

CH

NO

LO

GY

on

Oct

ober

30,

201

3 | h

ttp://

pubs

.acs

.org

P

ublic

atio

n D

ate

(Web

): O

ctob

er 4

, 201

3 | d

oi: 1

0.10

21/b

k-20

13-1

127.

ch00

4


The aqueous infusion is used as tonic in children and to treat dizziness andmental disorders in adults (16). Hypoxis is widely used traditionally particularlyin Zulu society for heart disease, bad dreams, anxiety, insanity, barrenness,intestinal parasites, urinary tract infections among other indications (11, 22).Related species mainly H. colchicifolia (syn. H. oligotricha), H obtuse, H.nyasica and H. angustifolia are also used for similar indications (11). In additionH. obtuse, which more commonly grows north of South Africa’s border is usedtraditionally for infertility in women, abdominal pains, heart pains, bile emesis,gonorrhea and for aphrodisiac effects (21).

Hypoxis also has ethnoveterinary uses. In South Africa Hypoxishemerocallidea and H.rigidula have been reportedly used for fertilityenhancement, general ailments, heartwater, and to prevent abortion in cattle bythe Tswana people (23) . Kambizi (24) has reported that fresh cut corms areapplied to the face by Xhosa women as facial treatments or used to treat burns.

In contemporary society, the use of hypoxis encompasses many of thetraditional uses and more recent indications. Today it is marketed both in its crudeunprocessed form (at traditional medicine (so-called muthi) markets) (7) andalso in pharmaceutical formulations and packaging as a phytomedicine in retailpharmacies. In both formats the marketing materials carry many unsubstantiatedclaims viz. HIV / AIDS, arthritis, myalgic encephalomyelitis (ME), hypertension,asthma, diabetes mellitus, cancer, arthritis, psoriasis, tuberculosis and epilepsy(22, 25–28). It is also increasingly being formulated into dermatological productswith purported antiviral and antifungal actions (11). In Germany, hypoxis extractshave been widely marketed since the late 1970’s for the treatment of prostateadenoma and benign prostate hypertrophy (BPH) (11, 29, 30). This indication isbased on the inhibition of 5α-reductase metabolism of testosterone by phytosterolsfrom hypoxis (11).

Dold and Cocks (7) estimated that trade in hypoxis exceeds 11 metric tonsper year in South Africa alone. Because of the high demand, hypoxis populationsare declining and under pressure (31). The use of corms is particularly destructiveand (32) investigated the possible use of the aerial parts as substitutes. They foundclear differences between the two plant parts both in chemical constitution andbiological activity making the substitution of corms for leaves less attractive.

Phytochemistry

Several compounds have been isolated from hypoxis species and some of themhave been linked to their putative biological activity. Hypoxoside, a norlignandiglucoside is an aglycone consisting of a diphenyl-1-en-4-yne-pentane unit (33)and has been isolated from all the common Hypoxis species (34). have suggestedthat this compound maybe unique to the genus. Hypoxoside is hydrolysed byβ-glucosidase to rooperol which appears to be the active bioavailable compound(26).

However it is for its high concentration of phytosterols that hypoxis is bestknown for, especially sterols, sterolins and stanols. The patent by (29) claimedthat aqueous extracts of H. hemerollicadea had phytosterol yield of 9 mg /

53

Dow

nloa

ded

by T

SHW

AN

E U

NIV

OF

TE

CH

NO

LO

GY

on

Oct

ober

30,

201

3 | h

ttp://

pubs

.acs

.org

P

ublic

atio

n D

ate

(Web

): O

ctob

er 4

, 201

3 | d

oi: 1

0.10

21/b

k-20

13-1

127.

ch00

4


100g, however this could not be reproduced in recent studies by (13). Theseworkers found less than 0.01% w/w final extract recovery they have dismissed thetherapeutic importance of sterolins in hypoxis based on that data. The likelihoodis that they were not using the same material and hence the differences areinconclusive.

The plant hormone (cytokinin) zeatin and it’s derivatives were isolated fromthe corms by Van Staden (35).

Biological Activity

It is fair to say that because of its high profile status in South African materiamedica, hypoxis has beenwell studied for its biological effects (Table 1). Methanolextracts of H. hemerocallidea corms showed no activity against Staphylococcusaureus, Escherichia coli, and Enterococcus faecalis (14). Using freshly harvestedcorms grown in the laboratory (32) previously showed that acetone and ethanolextracts of the leaves had relatively good activity against both E. coli (MIC < 0.31mg /ml) and to some extent Pseudomonas aeruginosa (MIC < 0.61 mg / ml). Theaerial parts of hypoxis have not been previously investigated so this study wasimportant in showing their possible utility.

Steenkamp et al. (36) showed inhibition of E. coli by both water and ethanolicextracts of H. hemerocallidea with MIC of 62.5 ug / ml, though they estimatedthat it would not translate to a therapeutic dose in humans (based on the dosage).They further suggested that the antimicrobial activity maybe another reason whyhypoxis is used in prostatitis and prostate indications.

Hypoxoside and rooperol showed good activity against E. coli and S. aureus,with the latter being more active than the positive control (neomycin) (37). Theyalso possess good antimuagenic and cytotoxic properties (38)

Sathegke (14) showed that methanol extracts of hypoxis is non-toxic in acytcoxicity assay done using Vero cells (African green monkey kidney cell line)and no activity was seen in HeLa cancer cell line. H. iridifolia and H. rigidulashowed slightly better activity in the HeLa cytotoxicity assays. Albrecht et al(26) have previously reported that rooperol, the hydrolytic product of hypoxosideshowed activity against HeLa cells under 10 µg/ml, while the glycoside wasinactive in the same cell line.

Cytotoxic activity against HeLa, HT-29 and MCF-7 cancer cells appearedto increase when β-glucosidase was added to H. hemerocallidea which seemedto imply that there were certain compounds (other than hypoxoside) which werebeing hydrolyzed to active metabolites (39)

Van der Merwe et al (40) demonstrated that rooperol inhibits leucotrienesynthesis in leukocytes and prostaglandin synthesis in platelet microsomes, thusshowing in vitro antioxidant and anti-inflammatory activity. Good free radicalscavenging ability was of aqueous and ethanolic extracts of H. hemerocallideawas shown by Steenkamp et al (36). Antioxidant and free radical scavengingactivities of rooperol has been confirmed in various assays (11, 18, 33) as wouldbe expected of most phenolic compounds.

54

Dow

nloa

ded

by T

SHW

AN

E U

NIV

OF

TE

CH

NO

LO

GY

on

Oct

ober

30,

201

3 | h

ttp://

pubs

.acs

.org

P

ublic

atio

n D

ate

(Web

): O

ctob

er 4

, 201

3 | d

oi: 1

0.10

21/b

k-20

13-1

127.

ch00

4


Ojewole (25) found that an aqueous decoction of the corms of hypoxishad significant antinociceptive and anti-inflammatory activity which was dosedependent (50 – 800 mg / kg p.o.). In the same study, hypoxis extract showedhypoglycemia in both normal and streptozotocin (STZ)-induced diabetes mellitusrats. Gaidamashvili and Van Staden (41) showed that lectins isolated from H.hemerocallidea may partly explain the anti-inflammatory activity as it eliciteda 29% inhibition of cyclooxygenase enzymes which catalyze the conversionof arachidonic acid to prostaglandin. In a study by Laporta et al (37), usingconcentrations below 0.5 mg / ml, there was no inhibition of COX-1 and COX-2by either the crude extract or the compound hypoxoside. Rooperol, howevershowed strong inhibition against both COX enzymes with a COX-2 / COX-1 IC50ratio of 2. It is thought that the compound exerts it’s anti-inflammatory actions byalso inhibiting the production of NF-κB, AP-1 and similar transcriptional factorsimportant in inflammatory processes (42)

Ojewole (43) has attempted to validate the ethnobotanical use of hypoxis inmanaging hysterical fits and epilepsy. Using a rat model, he found that aqueouscorm extracts (100 – 800 mg / kg i.p.) delayed the onset of, and significantlyinhibited, seizures. In other similar studies in rodent models, Ojewole andhis colleagues tried to validate the use of hypoxis in gastroinstestinal anduterine – related conditions, specifically, how do aqueous extracts of hypoxismodulate smooth muscle? (44–46). They found that hypoxis extracts reducedgastrointestinal motility, the frequency of defaecation and hence the severity ofdiarrhea in experimental rats (43). The uterolytic effects were also confirmed(46). In these experiments the muscle relaxant effects were found to be refractoryto β-adrenoceptor, cholinergic and histaminergic blockers leading the workers toconclude that the mode of action might be through a non-specific spasmolyticmechanism.

The dichloromethane (DCM) extract of H. colchicifolia leaves was the onlyone with significant activity of 16 plant extracts assayed for anthelmintic activityusing an in vitro colorimetric assaymeasuring free-living nematode larvae viability(47). H. hemerocallidea was inactive in this study.

A systematic review by (48) of various phytotherapies used to amelioratethe symptoms of Benign Prostatic Hyperplasia (BPH) Serenoa repens (sawpalmetto), Pygeum africanum (African plum) and H. hemerocallidea, showedthat the latter two improved urinary flow rates and symptoms compared toplacebo. Several clinical studies have demonstrated that the use of hypoxisextracts in BPH patients resulted in significant sustained symptomatic relief (49).The effects of hypoxis on the prostate have always been linked to the purportedoccurrence of high concentrations of phytosterols. These compounds are knownto inhibit 5α-reductase, the enzyme catalyzing the conversion of testosterone todihydroxytestorone (DHT).

BPH is prevalent in 50% of men over 50 years of age and in 90% of menover 80 years old and it is known to depend on androgens, especially DHT (50).Inhibitors of 5α-reductase can also be used for male pattern baldness, hirsutismand prostate cancer. Hypoxis has been widely marketed and used for prostatedisorders but there is need for more studies especially in light of recent findingsthat concentration of phytosterols in the species may actually be much lower than

55

Dow

nloa

ded

by T

SHW

AN

E U

NIV

OF

TE

CH

NO

LO

GY

on

Oct

ober

30,

201

3 | h

ttp://

pubs

.acs

.org

P

ublic

atio

n D

ate

(Web

): O

ctob

er 4

, 201

3 | d

oi: 1

0.10

21/b

k-20

13-1

127.

ch00

4


previously recorded (13). When this is considered in the light of the efficacydemonstrated in the systematic review of Dedhia and McVary (48), it may implythat other compounds which are yet to be identified or tested are responsible forthe purported activity.

Phytosterols from hypoxis (mainly stigmasterol, β-sitosterol, brassicasteroland ergosterol) are also marketed for their anti-lipidemic, cholesterol - loweringactions. They accomplish this inhibiting Delta24 ( δ 24) reductase enzymes in thecholesterol synthetic pathway (51). The lipid lowering effects of phytosterols arehowever equivocal because the bioavailability of these compounds is variable anddependant on formulation and other co-ingested foods (39)

The putative anti-inflammatory, antidiabetic and immune modulatingproperties of hypoxis have been attributed to β-sitosterol (52). The amountof sitosterol in hypoxis on average is variable. A study by (53) on immunemodulation showed that hypoxis extract was inferior to control in the survivalrates of FIV+ (Feline immunodeficiency virus infected) laboratory cat model.However, a sitosterol enriched product showed significantly improved survivalrates.

Toxicology and Adverse Effects

The African Herbal Pharmacopeia (54) suggests that oral ingestion ofhypoxoside showed no toxicity, and no lethality was seen in the brine shrimpassays nor cytotoxicity in Vero monkey cells.

However, it would appear that the use of crude herbal extracts of hypoxishas caused some concern. A study on renal function of wistar rats after bothacute and chronic exposure to aqueous H. hemerocallidea extracts found thatthere was impaired function with significant decrease in glomerular filtration rate(GFR) and increased plasma creatinine concentration (55). A human study on thesafety and efficacy of hypoxis extracts in HIV positive patients in South Africawas prematurely terminated by regulatory authorities reportedly because of bonemarrow suppression and immune suppression which has been also been reportedin a feline study (56). Steroids are known to be both immunesuppressive andmay cause osteoporosis (57) and this maybe evidence of the high concentrationof steroidal compounds in hypoxis.

In mice the LD50 of aqueous extracts of the corm of hypoxis was about 2g /kg meaning that the species shows low acute toxicity (58). Low doses of alcoholicand aqueous extracts of hypoxis, while causing a significant increase of weight insuckling rats, did not show any morphometric changes in the small intestine of thetest animals (59). These workers concluded that hypoxis had no adverse effectson suckling rats.

Dichloromethane and 90% methanol aqueous extracts of hypoxis showedno mutagenic or antimutagenic activity in the Ames Salmonella / microsomemutagenicity assay (60).

Daily doses of up to 3.2 g of hypoxis extract showed no clinical toxicityor adverse changes in biochemical or haematological measurements in a phase Iclinical trial in human lung cancer patients (61). While hypoxis has generally been

56

Dow

nloa

ded

by T

SHW

AN

E U

NIV

OF

TE

CH

NO

LO

GY

on

Oct

ober

30,

201

3 | h

ttp://

pubs

.acs

.org

P

ublic

atio

n D

ate

(Web

): O

ctob

er 4

, 201

3 | d

oi: 1

0.10

21/b

k-20

13-1

127.

ch00

4


proved to cause little toxicity, it is the potential for drug-herb interactions whichstill requires more extensive research. This is an increasingly important directionof research as the concomitant ingestion of herbs with pharmaceuticals is commonespecially in the treatment of HIV / AIDS (62). Therefore the potential for drug-herb adverse reactions is high. Nair et al. (10) have shown that hypoxis inhibitshuman drug metabolizing enzymes, CYP3A5, 3A4 and CYP19 by 11%, 33% and41% respectively while rooperol showed almost total inhibition of CYP3A4 and3A5. At concentrations of 5 mg / ml, hypoxis extracts showed high induction ofthe polyglycoprotein (Pg-p) transporter. No effect was shown on Pg-p by sterolsor rooperol (10).

Future Directions of Research

Liu et al (42) have recently for the first time used a colitis model todemonstrate that methanolic extracts of hypoxis ameliorates severe typhlocolitisin mice. The extract reduced weight loss, severity of bacteria – induced colitis,neutrophil infiltration and intestinal epithelial proliferation making hypoxis andit’s constituents an interesting lead in the search for prophylactic therapies forinflammatory bowel diseases. However the extract did not show similar efficacyin a non-bacteria-induced, dextran sodium sulfate (DSS) – induced colitis model.This is certainly an interesting and innovative direction in which research canmove.

There remain many unanswered questions e.g. environmental variation andhow it impacts on the chemistry and biological activity of hypoxis, the apparentlycontentious issue of the amounts of sterols and sterolins and their putative activity.Despite all the work that has been done so far, there remains a need to understandthe phytochemistry of hypoxis in it’s entirety and then to test the compounds invarious in vitro and in vitro assays. Finding the bioactive compound (s) may leadto the progression of such a compound in the pharmaceutical drug pipeline and /orto the standardization of hypoxis extracts.

Conclusion

Hypoxis hemerocallidea is an important medicinal and dietary plant inSouthern Africa. However it’s contemporary use (particularly in HIV / AIDSand so-called immune-boosting products) has been controversial and political.This may have compromised the scientific research into it’s use in these areas.There are some important data which have been gathered from in vitro and rodentstudies which may form a good basis for the design of further pre-clinical studies.However there is a general lack of extensive phytochemical studies which maybe the first step towards developing evidence – based botanical / phytomedicineproducts.

57

Dow

nloa

ded

by T

SHW

AN

E U

NIV

OF

TE

CH

NO

LO

GY

on

Oct

ober

30,

201

3 | h

ttp://

pubs

.acs

.org

P

ublic

atio

n D

ate

(Web

): O

ctob

er 4

, 201

3 | d

oi: 1

0.10

21/b

k-20

13-1

127.

ch00

4


AcknowledgmentsI wish to thank Dr. Learnmore Kambizi (CPUT) for proofreading the final

draft and useful comments.

References1. Chavunduka, G. Traditional Medicine in Modern Zimbabwe; University of

Zimbabwe Publications: Zimbabwe,1994.2. Milan, F.; Arnsten, J.; Klein, R.; Schoenbaum, E.; Moskaleva, G.; Buono, D.;

et al. Use of complementary and alternative medicine in inner-city personswith or at risk for HIV Infection. AIDS Patient Care STDs. 2008, 22, 811–6.

3. Monera, T.; Wolfe, A.; Maponga, C.; Benet, L.; Guglielmo, J. Moringaoleifera leaf extracts inhibit 6 beta-hydroxylation of testosterone by CYP3A4.J. Infect. Dev. Countries 2008 (2), 379–83.

4. WHO. Traditional Medicine Strategy 2002-2005; World Health Organization,2002.

5. Cunningham, A. Herbal medicine trade: a hidden economy. Indicator SA.1989, 6 (51-54).

6. Mander, M.Marketing of indigenous medicinal plants in South Africa - A casestudy in KwaZulu Natal; FAO: Rome, 1998.

7. Dold, A.; Cocks, M. The trade in medicinal plants in the Eastern CapeProvince, South Africa. S. Afr. J. Sci. 2002, 98, 589–97.

8. Moodie, G.; Rooyen, K. V. HIV Concoction Slammed As Toxic: Foodcombination recommended by Aids dissident to SA’s health minister has nosupport from science, local researchers say. Sunday Times 2003March30.

9. Terreblanche, C. HIV warning on African potato; http://wwwiolcoza/news/south-africa/hiv-warning-on-african-potato-1109328, July 15 2003.

10. Nair, V.; Foster, B.; Arnason, J.; Mills, E.; Kanfer, I. In vitro evaluationof human cytochrome P450 and P-glycoproten-mediated metabolism ofsome phytochemicals in extracts and formulations of African potato.Phytomedicine 2007a, 14, 498–507.

11. Drewes, S. E.; Elliot, E.; Khan, F.; Dhlamini, J. T.; Gcumisa, M. S. Hypoxishemerocallidea--not merely a cure for benign prostate hyperplasia. J.Ethnopharmacol.. 2008, 119 (3), 593–8Epub 2008/07/08.

12. Betto, P.; Gabriele, R.; Galeffi, C. Determination of the norlignanglucosides of Hypoxidaceae by high-performance liquid chromatography. J.Chromatogr., A 1992, 594, 131–5.

13. Nair, V.; Kanfer, I. Sterols and sterolins in Hypoxis hemerocallidea (Africanpotato). S. Afr. J. Sci. 2008, 104, 322–3.

14. Sathekge, N. Comparison of secondary metabolite content and antimicrobialactivity of four Hypoxis species used in traditional medicine [MSc];University of Pretoria: Pretoria, 2010.

15. Wyk, B.-E. V.; Oudtshoorn, B. V.; Gericke, N. Medicinal plants of SouthAfrica; Briza Publications: Pretoria, 1997.

16. Mukinda, J.; Eagles, P. The South African PharmacopieaMonograph Project:South African Traditional Medicines Research Group (SATMERG); 2010.

58

Dow

nloa

ded

by T

SHW

AN

E U

NIV

OF

TE

CH

NO

LO

GY

on

Oct

ober

30,

201

3 | h

ttp://

pubs

.acs

.org

P

ublic

atio

n D

ate

(Web

): O

ctob

er 4

, 201

3 | d

oi: 1

0.10

21/b

k-20

13-1

127.

ch00

4


17. Singh, Y. Hypoxis: yellow stars of horticulture, folk remedies andconventional medicine. Veld Flora 1999, 85, 123–5.

18. Laporta, O.; Perez-Fons, L.; Mallvia, R.; Caturla, N.; Micol, V. Isolation,characterization and antioxidant capacity assessment of the bioactivecompounds derived from Hypoxis rooperi corm extracts (African potato).Food Chem. 2007b, 101, 1425–37.

19. Green, J. Manto’s concoction ‘could be harmful’ 2003 10 May 2011;Available from http://www.iol.co.za/news/south-africa/manto-s-concoction-could-be-harmful-1.214582.

20. Amusan, O. O. G.; Sukati, N. A.; Dlamini, P. S.; Sibandze, F. G. Some Swaziphytomedicines and their constituents. Afr. J. Biotechnol. 2007, 6, 267–72.

21. Gelfand, M.; Mavi, S.; Drummond, R.; Ndemera, B. The Traditional MedicalPractitioner in Zimbabwe, 2nd ed.; Mambo Press:Gweru, 1993.

22. Watt, J.; Breyer-Brandwijk, M. Medicinal and Poisonous Plants of Southernand Eastern Africa, 2nd ed.; Livingstone: London, 1962.

23. Merwe, D. V. d.; Swan, G.; Botha, C Use of ethnoveterinary medicinal plantsin cattle by Setswana-speaking people in the Madikwe area of the North WestProvince of South Africa. J. S. Afr. Vet. Assoc. 2001, 72, 189–96.

24. Kambizi, L. Herbal remedies for skin care in the Eastern Cape; IndigenousPlant Use Forum Conference Abstract; July 2012; University of Venda,Thoyohandou.

25. Ojewole, J. A. O. Antinociceptive, anti-inflammatory and antidiabeticproperties of Hypoxis hemerocallidea Fisch. & C.A. Mey. (Hypoxidaceae)corm [‘African Potato’] aqueous extract in mice and rats. J. Ethnopharmacol.2006, 103 (1), 126–34.

26. Albrecht, C. Hypoxoside: a putative prodrug for the treatment ofmalignancies, HIV infections, and inflammatory conditions. SAMJ 1995, 85,302–7.

27. Hutchings, A.; Scott, A; Lewis, G.; Cunningham, A. Zulu Medicinal Plants -An inventory, 1st ed.; University of Natal Press: Pietermaritzburg, 1996.

28. Van Wyk B-E, G. N. People’s Plants: a guide to useful plants of southernAfrica; Briza Publications: Pretoria, 2000.

29. Pegel, K. H.; Liebenberg, R. W. (inventors) Extraction of phytosterolglycosides from Hypoxis tubers; Germany1973.

30. Tyler, V. Plant drugs in the twenty-first century. Econ. Bot. 1986, 40, 279.31. Hölscher B.. Hypoxis hemerocallidea Fisch., C.A.Mey. & Avé-Lall; 2009.

10 May 2011. Available from: http://www.plantzafrica.com/planthij/hypoxishemero.htm

32. Katerere, D. R.; Eloff, J. N. Anti-bacterial and anti-oxidant activity of Hypoxishemerocallidea (Hypoxidaceae): Can leaves be substituted for corms as aconservation strategy? S. Afr. J. Bot. 2008, 74 (4), 613–6.

33. Nair, V. D.; Dairam, A.; Agbonon, A.; Arnason, J. T.; Foster, B. C.;Kanfer, I. Investigation of the antioxidant activity of African potato (Hypoxishemerocallidea). J. Agric. Food Chem. 2007b, 55 (5), 1707–11Epub2007/02/14.

34. Nair, V. D.; Kanfer, I. High-performance liquid chromatographic method forthe quantitative determination of Hypoxoside in African potato (Hypoxis

59

Dow

nloa

ded

by T

SHW

AN

E U

NIV

OF

TE

CH

NO

LO

GY

on

Oct

ober

30,

201

3 | h

ttp://

pubs

.acs

.org

P

ublic

atio

n D

ate

(Web

): O

ctob

er 4

, 201

3 | d

oi: 1

0.10

21/b

k-20

13-1

127.

ch00

4


hemerocallidea) and in commercial products containing the plant materialand/or its extracts. J. Agric. Food Chem. 2006, 54 (8), 2816–21.

35. Van Staden, J. Constituents of Hypoxis rooperi, a valuable medicinal plant inSouth Africa. Dtsch. Apoth. Ztg. 1981, 33, 460–4.

36. Steenkamp, V.; Gouws, M. C.; Gulumian, M.; Elgorashi, E. E.; Staden, J. v.Studies on antibacterial, anti-inflammatory and antioxidant activity of herbalremedies used in the treatment of benign prostatic hyperplasia and prostatitis.J. Ethnopharmacol. 2006, 103, 71–5.

37. Laporta, O.; Funes, L.; Garzon, M. T.; Villalain, J.; Micol, V. Role ofmembranes on the antibacterial and anti-inflammatory activities of thebioactive compounds from Hypoxis rooperi corm extract. Arch. Biochem.Biophys. 2007, 467 (1), 119–31.

38. Albrecht, C. Hypoxoside as a putative non-toxic, multi-functional prodrugfor the treatment of cancer, HIV-AIDS and inflammatory conditions. In:2nd IOCD international Symposium; Hostettman, K., Chinyanganya, F.,Maillard, M., Wolfender, J., Eds.; University of Zimbabwe Press: VictoriaFalls, Zimbabwe, 1996.

39. Boukes, G. J. The in vitro biological activities of three Hypoxis species andtheir active compounds. Ph.D. Thesis, NMMU, 2010.

40. Van der Merwe, M. J.; Jenkins, K.; Theron, E.; van der Walt, B. J. Interactionof the di-catechols rooperol and nordihydroguaiaretic acid with oxidativesystems in the human blood. Biochem. Pharmacol. 1993, 45 (2), 303–311.

41. Gaidamashvili, M.; Staden, . Jv. Prostaglandin inhibitory activity by lectin-like proteins from South African medicinal plants. S. Afr. J. Bot. 2006, 72,661–3.

42. Liu, Z.; Wilson-Welder, J.; Hostetter, J.; Jergens, A.; Wannemuehler, M.Prophylactic treatment with Hypoxis hemerocallidea corm (African potato)methanolic extract ameliorates Brachyspira hyodysenteriae-induced murinetyphlocolitis. Exp. Biol. Med. (Maywood) 2010, 235 (2), 222–30.

43. Ojewole, J. A. Anticonvulsant activity of Hypoxis hemerocallidea Fisch. &C. A. Mey. (Hypoxidaceae) corm (‘African potato’) aqueous extract in mice.Phytother. Res. 2008, 22 (1), 91–6.

44. Ojewole, J. A.; Awe, E. O.; Nyinawumuntu, A. Antidiarrhoeal activityof Hypoxis hemerocallidea Fisch. & C. A. Mey. (Hypoxidaceae) Corm(‘African potato’) aqueous extract in rodents. Phytother. Res. 2009, 23 (7),965–71.

45. Ojewole, J. A.; Olayiwola, G.; Nyinawumuntu, A. Bronchorelaxant propertyof ‘African potato’ (Hypoxis hemerocallidea corm) aqueous extract in vitro.J. Smooth Muscle Res. 2009b, 45 (5), 241–8.

46. Nyinawumuntu, A.; Awe, E. O.; Ojewole, J. A. Uterolytic effect of Hypoxishemerocallidea Fisch. & C.A. Mey. (Hypoxidaceae) corm [‘African Potato’]aqueous extract. J. Smooth Muscle Res. 2008, 44 (5), 167–76.

47. Aremu, A.; Ndhlala, A.; Fawole, O.; Light, M.; Finnie, J.; Staden, J. V. Invitro pharmacological evaluation and phenolic content of ten South Africanmedicinal plants used as anthelmintics. S. Afr. J. Bot. 2010, 76, 558–66.

48. Dedhia, R.; McVary, K. Phytotherapy for lower urinary tract symptomssecondary to benign prostatic hyperplasis. J. Urol. 2008, 179, 2119–25.

60

Dow

nloa

ded

by T

SHW

AN

E U

NIV

OF

TE

CH

NO

LO

GY

on

Oct

ober

30,

201

3 | h

ttp://

pubs

.acs

.org

P

ublic

atio

n D

ate

(Web

): O

ctob

er 4

, 201

3 | d

oi: 1

0.10

21/b

k-20

13-1

127.

ch00

4


49. Lowe, F. C.; Dreikorn, K.; Borkowski, A.; Braeckman, J; Denis, L.; Ferrari, P.;et al. Review of recent placebo-controlled trials utilizing phytotherapeuticagents for treatment of BPH. Prostate. 1998, 37 (3), 187–93.

50. Carson, C.; Rittmaster, R. The role of dihydrotestosterone in benign prostatichyperplasia. Urology 2003, 61, 2–7.

51. Fernández, C. S. Y.; Ferruelo, A. J.; Gómez-Coronado, D.; Lasunción, M.A. Inhibition of cholesterol biosynthesis by Delta22-unsaturated phytosterolsvia competitive inhibition of sterol Delta24-reductase in mammalian cells.Biochem. J. 2002, 366 (Pt 1), 109–19.

52. Bouic, P. J. D. The role of phytosterols and phytosterolins in immunemodulation: a review of the past 10 years. Curr. Opin. Clin. Nutr. Metab.Care 2001, 4 (6), 471–5.

53. Lamprecht, J.; Liebenberg, R.; Freestone, M.; Bouic, P.; Clark, A;Jaarsveld, P. V. A comparison of the survival benefit provided by putativeimmune modulators in the FIV+ (Feline immunodeficiency virus infected)laboratory cat model. Int. Conf. AIDS 2000, 13 abstract no. TuPeA3021.

54. Brendler, T.; Eloff, J.; Gurib-Fakim, A.; Phillips, L. African Herbal.Pharmacopeia 2010, 324.

55. Musabayane, C. T.; Xozwa, K.; Ojewole, J. A. Effects of Hypoxishemerocallidea (Fisch. & C.A. Mey.) [Hypoxidaceae] corm (African Potato)aqueous extract on renal electrolyte and fluid handling in the rat. Ren Fail.2005, 27 (6), 763–70.

56. Niekerk, J. d. V. Food for thought. S. Afr. Med. J. 2003, 93, 297.57. Brunton, L.; Goodman, L.; Blumenthal, D.; Buxton, I. Goodman and

Gilman’s Manual of Pharmacology and Therapeutics; McGraw Hill: NewYork, 2008.

58. Ojewole, J. A. Antinociceptive, anti-inflammatory and antidiabetic propertiesof Hypoxis hemerocallidea Fisch. & C.A. Mey. (Hypoxidaceae) corm[‘African Potato’] aqueous extract in mice and rats. J. Ethnopharmacol.2006, 103 (1), 126–34.

59. Erlwanger, K. H.; Cooper, R. G. The effects of orally administered crudealcohol and aqueous extracts of African potato (Hypoxis hemerocallidea)corm on the morphometry of viscera of suckling rats. Food Chem. Toxicol.2008, 46 (1), 136–9Epub 2007/08/25.

60. Reid, K.; Maes, J.; Maes, A.; Staden, J. v.; Kimpe, N. D.; Mulholland, D.; etal. J. Ethnopharmacol 2006, 106, 44–50.

61. Smit, B; Albrecht, C; Liebenberg, R; Kruger, P; Freestone, M; Gouws, L.;et al. A phase I trial of hypoxoside as an oral prodrug for cancer therapy -absence of toxicity. S. Afr. Med. J. 1995, 85, 865–70.

62. Bica, I.; Tang, A.; Skinner, S.; Spiegelman, D.; Knox, T.; Gorbach, S.; etal. Use of complementary and alternative therapies by patients with HumanImmunodeficiency Virus disease in the era of Highly Active AntiretroviralTherapy. J. Altern. Complementary Med. 2003, 9, 65–76.

61

Dow

nloa

ded

by T

SHW

AN

E U

NIV

OF

TE

CH

NO

LO

GY

on

Oct

ober

30,

201

3 | h

ttp://

pubs

.acs

.org

P

ublic

atio

n D

ate

(Web

): O

ctob

er 4

, 201

3 | d

oi: 1

0.10

21/b

k-20

13-1

127.

ch00

4


Hypoxis hemerocallidea (African Potato): A Botanical Whose Time Has Come?

Documents

Transcript of Hypoxis hemerocallidea (African Potato): A Botanical Whose Time Has Come?